1. Field of the Invention
The present invention relates to a process for producing a carbonic acid ester. A carbonic acid ester is an industrially important compound as an intermediate and solvent for the production of polymers and drugs and agricultural chemicals.
2. Description of the Prior Art
A carbonic acid ester is industrially produced by the reaction of an alcohol with phosgene. This process, however, has a disadvantage that phosgene is highly toxic and the reaction of an alcohol with phosgene produces highly corrosive hydrochloric acid as a by-product.
There is a process for producing a carbonic acid ester without using phosgene. According to this method, an alcohol, carbon monoxide, and oxygen are reacted with one another in the presence of a copper compound alone or together with a platinum group metal compound and a basic compound. (See Japanese Patent Publication Nos. 11129/1970 and 8816/1986 and Japanese Patent Laid-open No. 185542/1983.) This process also has a disadvantage in that the catalyst, especially the copper component, is poor in solubility and the formation of the carbonic acid ester is rather slow. It has an additional disadvantage in that a large amount of carbon dioxide as a by-product is formed as the result of the combustion of carbon monoxide and the decomposition of carbonic acid ester.